Ch 11 Introduction to Atoms. The Beginning of Atomic Theory Democritus & Aristotle Can you cut a piece of paper in half and cut those halves in half and.

Ch 11 Introduction to Atoms

The Beginning of Atomic Theory Democritus & Aristotle Can you cut a piece of paper in half and cut those halves in half and continue until you are left with 1 particle? If you could do this you would end up with what Democritus called an _________= ______________________ Aristotle _____________ with democrituss idea. He believed that ___________________________________ Who was correct? Aristotle or Democritus??

The Beginning of Atomic Theory ____________________was correct! Matter is made of particles which we call ___________. Atom -

The Beginning of Atomic Theory Dalton 1803 Daltons atomic theory was based on _________________! All substances are made of ______ Atoms are small particles that cannot be _____, _______, or _________. Atoms of the same element are _________ and atoms of different elements are _________. Atoms join with other atoms to make _____ substances.

The Beginning of Atomic Theory New information didnt quite fit with _______ ideas. His atomic theory had to be _________. Thomson- 1897 Discovered the ____________ charged particles There are __________ inside the atom. Atoms can be broken down further. (Dalton thought atoms were solid spheres so hes wrong)

CATHODE-RAY TUBE A positively charged plate was attracted to a ______. Therefore, the beam must be made up of ________ charges. Thomson concluded these negative charges are _______ in every kind of _______.

The Beginning of Atomic Theory ________- A subatomic particle that has a negative charge. Thomson described his model of the atom like plum pudding. Today you might call it the ______________ _____ model. (with electrons represented by _________________.)

The Beginning of Atomic Theory Rutherford- 1909 Rutherford was a _____________ of Thomsons. He tried to help prove Thomson theory was _______ and ended up proving him ______! He aimed a beam of small, _________________ ( particles) at a thin piece of gold foil. Photo paper behind the gold recorded where the charged particles hit. Surprising Results He thought the particles would _______________ the gold in a straight line. Some particles were ________. Some shot right ______.

Rutherfords Gold-Foil Experiment Rutherford determined an atom must be mostly ______ ______ with a tiny part made of highly dense material.

Rutherfords Model ________ The centrally located, tiny, extremely dense positively charged part of an atom.

The Beginning of Atomic Theory Bohr 1913 Niels Bohr proposed that electrons move around the nucleus in _______________________________. Electrons can jump from path to path but cannot exist in _____________ paths. Think of ________ on a ladder. You can stand on the rungs, but not ________ the rungs. Or think of planets in our solar system they do not stray off the set path or ___________.

The Modern Atomic Theory Schr dinger and Heisenberg Electrons ________ travel in definite paths as Bohr suggested. The exact path of the electron ______ be predicted. There are regions where it is likely to be found called ______ __________.

4.2 The Atom How small is an _____? A penny contains __________ atoms. (20,000,000,000,000,000,000,000 atoms) An atom is made up of _______, _______, and _________. The Nucleus Protons The mass of protons are measured in atomic mass units (amu). Each proton has a mass of __________ _________- Particles in the nucleus that have ___ electrical charge. Neutrons have a mass of 1 amu. (Same as _________)

The Atom Outside the nucleus _________ are found outside the nucleus. They have a _______ charge. They have a mass of almost _____. If the number of protons __________ the number of electrons, the atom is ______________

HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Atoms of different elements have different numbers of ____________. No two elements have the same _____________. Atomic number is the number of ________ in an atom. All atoms of the _____________ have the _________ atomic number.

HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? So how do we figure out the number of neutrons for an atom? The number of _____________ = the number of _______________ Mass number The mass number does not include the mass of ____________ because they are so ___________and have very little effect.

HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Where do you find these numbers? On the ____________________ ! C C C # of neutrons = _________ - _________ # of neutrons in C = ____ - ____ C P + = N o = E - = ______ # __ + # __ # __ ___

HOW DO ATOMS OF DIFFERENT ELEMENTS DIFFER? Mass #Atomic #ProtonsNeutronsElectrons Li Be B C N O F Na k

DRAWING BOHR MODELS OF ATOMS Draw the nucleus and label with #p & #n Draw electron orbitals 1 st orbital can have ______ electrons only 2 nd and 3 rd ring can each have ______electrons Fill _____________________ Inner rings must be filled first before any electron enters a higher ring!!!!! Examples:

Changing Atoms If you change a persons hair color does it change who they are? Weight? What subatomic particle determines an atoms identity?___________ Therefore, the number of electrons and neutrons can change in the atom and it is still the same atom. If the number of protons __________ the number of electrons, the atom is ______________ If the number of protons ___________ the number of electrons, the atom becomes charged and we call it an _______. Positively charged ions Negatively charged ions -

ISOTOPES _________- Atoms that have the same number of protons, but have different numbers of neutrons. Examples: Hydrogen -1 and Hydrogen -2 Naming Isotopes Write the __________ of the element, followed by a hyphened and the _____________________ of the isotope. Ex. A hydrogen atom with 1 proton and 0 neutrons A hydrogen atom with 1 proton and 1 neutron

ISOTOPES Mass Number The sum of the _________________ in an atom. (__________ are not included.) Mass # = protons + neutrons Atomic Mass The _____________ of the masses of all the ___________ occurring isotopes of that element.

Solving the Atomic Mass Ex: Skittles consist of Orange 1 which is 25% of the Skittles and Red 2 which is 75% of skittles. Step1: change percents to decimals. Step 2: multiply the decimal by the mass Step 3: add the two answers together

Solving for Atomic Mass Ex: Chlorine-35 which is 76% of the Chlorine atoms and Chlorine-37 which is 24% of Chlorine atoms. Step1: change percents to decimals. Step 2: multiply the decimal by the mass Step 3: add the two answers together

Ch 11 Introduction to Atoms. The Beginning of Atomic Theory Democritus & Aristotle Can you cut a piece of paper in half and cut those halves in half and.

Documents

atom slide

thomson theory

daltons atomic theory

charged particles

hes wrong slide

small particles

atoms of different elements

piece of gold foil